11-811538,11-811538 Amdt A,11-811538-1,11-811538-1 Amdt A
三、章节号
36-11-32
四、适用机型
A330/A340
五、系统
36 PNEUMATIC
气源
六、安装位置
The Precooler is a component of the Air Bleed System installed in the engine pylon
预冷器是安装在发动机吊架上的引气系统的一个部件
七、部件原理
Detailed Description
详细描述
The bleed air precooler consists of a core assembly with a pan assembly welded at each end. The core assembly support plates, side plates and headers, as well as the pan assemblies, are made from corrosion resistant steel.
The core assembly consists of a series of tubes mounted in headers and separated by cooling air space. A flanged port is located on each pan assembly to provide inlet and outlet bleed air ports for the core assembly.
The Precooler admits charge (hot) air bleed from the HP (High-Pressure) or IP (IntermediatePressure) stages of the jet engine. It uses the engine fan air as a cooling air to precool charge air by thermal exchange. Hot air passes inside the precooler tubes, and the cooling air passes outside the tubes.
The engine bleed-air supply-system is installed in the nacelle and pylonof each engine.
发动机引气供应系统安装在每个发动机舱和吊架内。
An air-to-air Precooler Heat-Exchanger (PCE) controls the temperature of the engine bleed air supplied to the distribution system. The engine fan supplies cool air through a Fan Air Valve (FAV) to the PCE. A temperature control thermostat (THC), installed downstream of the PCE controls the butterfly plate of the FAV. This controls the quantity of cool air that enters the PCE.
This sub-system comprises the following components:
– a precooler exchanger
– a fan air valve associated with a control thermostat.
This sub-system enables the aircraft systems to be supplied with air under a normal temperature lower than or equal to 200⁰C. A second level of control at 150⁰C (adjustable) is available. It is activated by the BMC according to the demand of the air conditioning system.
The bleed air is cooled down by modulating the air flow bled from the engine fan through the precooler exchanger. At the precooler exchanger outlet, the control thermostat adjusts the fan air valve control pressure and thereby the valve butterfly position so as to limit the temperature at the above mentioned values.
The precooler exchanger ensures the following functions:
– To meet the required temperature for the air conditioning, wing anti ice and other sub-systems, the bleed air has to be cooled by an air-to-air heat exchanger called precooler exchanger.
– The precooler exchanger cools the hot air from the engine compressor by a heat exchange process using cold air bled from the engine fan (via the fan air valve).
– The precooler exchanger is tubular on the hot air side and the cooling air flows over the tubes in a crossflow configuration.